Work on the simplification of the enzyme immunoassay will be continued. Our ultimate goal is to develop a "dip stick" type method. Regarding the peroxidase-labeled antibody method, we will continue to improve the method of conjugation of peroxidase to immunoglobulin and the preservation of tissues. Development of fixatives for non-protein antigens such as steroids, nucleic acids and cAMP will expand the usefulness of the method to more fields of biological investigation. BIBLIOGRAPHIC REFERENCES: H. Miyamoto and P.K. Nakane. Life cycle of vaccinia virus: studied by peroxidase-labeled antibody method. In: First International Symposium on Immunoenzymatic Techniques, INSERM Symposium No.2. Feldmann et al., eds., North Holland Publishing Company, Amsterdam, 1976, pp.433-442. P.K. Nakane. Application of enzyme-labeled antibody methods for the ultrastructural localization of hormones: review. In: Recent Progress in Electron Microscopy of Cells and Tissues. Yamada et al., IgakuShoin, Tokyo, 1976, pp. 189-200.